A custom designed optical system is reported for tissue spectroscopy over four wavelengths of 677 nm, 780 nm, 830 nm, and 977 nm. A high speed laser driver is designed with a flat frequency response using pre-emphasis circuit. The driver is employed for high current in high power lasers. Phantom and intra-lipid experiments are performed to extract optical parameters of a turbid media. Broadband measurement is used to extract optical parameters of the phantom model simulating a breast tissue using forward scattering models. The optical parameters () are extracted with a very good accuracy.
"An investigation into the effects of static background structure on the images of change in optical properties was presented. Mu et al. (2003) reported that phantom and Intra-lipid experiments were performed to extract optical parameters of a turbid media. Broadband measurement was conducted to extract optical parameters of the phantom model simulating breast tissue using forward scattering models. "
[Show abstract][Hide abstract] ABSTRACT: Diffuse optical tomography (DOT) is a new tomographic technique, which is non-invasive and does not involve radiation exposure. In this paper, a self-developed near infrared (NIR) diffuse optical tomography instrument is described, and phantoms com-posed of Intra-lipids are discussed. The NIR optical characteristics of the homogenous Intra-lipid phantoms are measured to construct a set of databases at various concentrations, and further analysis using fitting curves is presented as well. Additionally, a pseudo-model technique for imitating biological tissues is proposed and implemented. This pseudo-model can be used to represent the same optical characteristics as real tissues, meaning that it is a viable alternative to cope with measuring limitations. Experiments reveal good results when the pseudo-model employs 1% Intra-lipid as a background tissue that imitates pork and 3% Intra-lipid as an inclusion to mimic a bone. Due to the limitations of hardware nowadays, obviously, this pseudo-model will offer a great aid for the development and evaluation of a DOT system.
Journal- Chinese Institute of Engineers 03/2007; 30(2). DOI:10.1080/02533839.2007.9671245 · 0.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Microwave Photonics techniques are applied to functional near IR (fNIR) imaging systems, where absorption and scattering parameters of tissue is extracted using multi-wavelength spectroscopy. Clinical applications of fNIR systems to anesthesia and wound healing are also discussed.
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 01/2009; DOI:10.1109/LEOS.2009.5343362
[Show abstract][Hide abstract] ABSTRACT: This invited paper addresses various "microwave photonics" techniques developed for biomedical applications. The first application is using RF photonics technique for calibration of ultrasound transducers operating at high-frequencies without spatial field averaging compromise. In particular a broadband fiber-optic based hydrophone probe is reported for measurements of acoustic fields at the frequencies up to 100 MHz. In another application of microwave photonics, tissue spectroscopy is performed using multi-wavelength absorption and scattering in near infrared. A high speed and high power laser driver is designed with a flat frequency response using RC speed up circuits in high power lasers. Phantom experiments are performed to extract optical parameters. Multi-frequency data fitting algorithm is performed to extract optical parameters of the phantom model simulating a breast tissue. The optical parameters (mua, mus') are extracted with a very good accuracy. These low cost techniques are replacement for other expensive sub-centimeter spatial resolution medical imaging methods.
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